Wondering what are the causes of bipolar disorder?
Today’s medicine is advanced but sometimes, it struggles to give complete and satisfying answers about the causes and development of certain disorders, same is true for the bipolar disorder.
Why is it important to know the cause? Because the treatment of anything rests on addressing the cause.
Genes - The Key Players
Gender predisposes you to the development of the bipolar disorder. Bipolar disorder is of two main types namely the bipolar I disorder and the bipolar II disorder.
The bipolar I disorder effects both women and men at the same rate. However, bipolar II disorder is more common in women.
Women are more predisposed to developing the bipolar II disorder probably due to the genetics. Gender is a predisposing factor not a cause.
Genes are considered to be the key players in the development of the bipolar disorder. But no single gene is responsible for the disorder. It is a constellation of genes, a group , a complex ,probably and their interactions with each other and with other internal and external factors that leads to the bipolar disorder.
In Nutshell| Causes of Bipolar Disorder
✓ Females are more prone to bipolar II disorder.
✓ Genes play the major role in the causation of bipolar disorder.
✓ Tryptophan hydroxylase 2 gene that codes the enzyme for serotonin synthesis is involved.
✓ CACNA1C gene that codes the calcium channels is involved.
✓ Impaired functioning of the serotonin receptors.
✓ Structural variations can be present like the immature dentate gyrus.
TPH2 Gene and Serotonin Synthesis
Neurotransmitter systems (the system of chemicals in the brain) play a
significant role in the development of the disorder. But this is again
indirect. The genes responsible for the production of these chemicals
(neurotransmitters) undergo some changes and this leads to the impaired
functioning of these chemicals.
Tryptophan hydroxylase 2 gene, also known as (TPH2) gene is said to be part of
the development of the disorder. This gene is responsible for the synthesis of
the tryptophan hydroxylase. This is the main enzyme in the pathway which makes
serotonin. Serotonin is one of the hormones, which are responsible for mood
changes.
Also, this hormone regulates the day/night circle. That is why, if the hormone
is reduced or increased, behavioral changes will be observed in the patient.
Increased quantities of this hormone are associated with manic periods or
hypomanic periods. In this situation, the patient feels excited and he/she does
not need to sleep. He has high goals and great self-esteem.
The decreased quantities of serotonin, lead to depression, which is the other
specific set of symptoms, characteristic for bipolar disorder. Patients feel
sleepy and they have low self-esteem. In most cases, they have suicidal
thoughts and they feel unworthy.
CACNA1C gene and Calcium Channels Synthesis
The gene- CACNA1C could also be pointed as one of the causes of bipolar
disorder. This gene codes the information for the synthesis of substantial
calcium channel. This channel is important for conducting the impulses from one
neuron to another.
It is estimated that Lithium down regulates the quantity of these calcium
channel and this is the reason why patients are well influenced by a lithium
therapy. The studies have been carried out on mice and their brains were used
to get the required information.
Changes in the Brain Structure - The Immature Dentate Gyrus
Changes in the structure of the brain that are variation from normal can also
be the cause of bipolar disorder. Research is going on to find out clues on
this aspect. One such clue indicates the possibility of the presence of
immature cells in some parts of the brain that effect mood.
There is the of presence of immature dentate gyrus (part of the brain) in
persons suffering from bipolar disorder. Elevated levels of a certain chemical
(calretinin) have been found in the dentate region of the brain in people
suffering from bipolar disorder.
It suggests the presence of immature cells in
this area which are producing these chemicals. It implies that there may be structural
variations in the brain of the individual suffering from bipolar disorder.
Impaired Serotonin Receptors
Impaired functioning of the serotonin receptors is also considered a cause of
bipolar disorder. Receptor is the place on the cell where a certain chemical
binds. The place where serotonin binds on the cell is called the serotonin
receptor.
Serotonin is an important chemical in controlling our mood. When the chemical
binds on the cell, series of changes occurs in the cell and the corresponding response
of the chemical is produced. Some studies suggest that the serotonin type 3
receptors (5-HT(3)) are not functioning properly in the individuals suffering
from bipolar disorder.
Finding the causes of bipolar disorder is particularly important from the
treatment point of view. Once the cause is known measures can be taken to
address it and cure the disease. With on going research hopefully we better
understand bipolar disorder and come up with better treatment options in the
future.
References
Walton NM, Zhou Y, Kogan JH, Shin R, Webster M, Gross AK, Heusner CL, Chen Q, Miyake S, Tajinda K, Tamura K, Miyakawa T, Matsumoto Walton NM,M. (2012). Detection of an immature dentate gyrus feature in human schizophrenia/bipolar patients. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/22781168
Hammer C, Cichon S, Mühleisen TW, Haenisch B. (2012). Replication of functional serotonin receptor type 3A and B variants in bipolar affective disorder: a European multicenter study. Retrieved fromhttp://www.ncbi.nlm.nih.gov/pubmed/22832903
Return from Causes of Bipolar Disorder to Beating Depression
Return from Causes of Bipolar Disorder to What is Bipolar Disorder
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